Disclosed herein is a dual density disc comprising a dense outer tube comprising a metal oxide having a purity of greater than 92%; and a porous core comprising a metal oxide of a lower density than a density of the dense outer tube; wherein the porous core has a metal oxide purity of greater than 99%; where the dense outer tube has an inner tapered surface.

A wafer boat according to the present disclosure includes a plurality of support columns, each having a pillar shape and comprising a plurality of grooves configured to have a wafer placed thereon, and support plates configured to support both end portions of the plurality of support columns, respectively. Each of the plurality of support columns are formed of a ceramic containing aluminum oxide or silicon carbide as a main constituent, and an outer side surface of the plurality of support columns is a ground surface and/or a polished surface.

Disclosed is a pottery greenware material by which a pottery having both productivity and quality can be produced with a high degree of freedom depending on an intended use thereof. The pottery greenware material includes a first greenware material and a second greenware material; both the first greenware material and the second greenware material including, as chemical species, SiO.sub.2, Al.sub.2O.sub.3, and either one or both of K.sub.2O and Na.sub.2O; and an average particle diameter (D2) of the second greenware material being smaller than an average particle diameter (D1) of the first greenware material.

A preform intended for the production of a dental prosthesis. The preform includes a group of agglomerated ceramic, glass-ceramic or glass particles, such that, as volume percents: more than 40% and less than 90% of the particles of said group have a size greater than 0.5 μm and less than 3.5 μm, said particles hereinafter being denoted “enamel particles”, and more than 10% and less than 60% of the particles of said group have a size greater than 3.5 μm and less than 5.5 μm, said particles hereinafter being denoted “dentine particles.” The microstructure of the preform is such that there is an axis X, termed “axis of variation”, along which the Ve/(Ve+Vd) ratio changes continuously, Ve and Vd denoting the volume percents of enamel particles and of dentine particles, respectively. The enamel and dentine particles representing, together, more than 90% of the volume of the agglomerated particles.

A method for manufacturing a dense layer that includes: supplying a substrate and a suspension of non-agglomerated nanoparticles of a material P; depositing a layer on the substrate using the suspension; drying the layer thus obtained; and densifying the dried layer by mechanical compression and/or heat treatment. The method is characterised in that the suspension of non-agglomerated nanoparticles of material P includes nanoparticles of material P having a size distribution having a value of D50. The distribution includes nanoparticles of material P of a first size D1 between 20 nm and 50 nm, and nanoparticles of material P of a second size D2 characterised by the value D50 being at least five times less than that of D1, or the distribution has a mean size of nanoparticles of material P less than 50 nm, and a standard deviation to mean size ratio greater than 0.6.

The invention relates to a solid electrolyte including partially stabilized zirconia, a producing method thereof, and a gas sensor including a solid electrolyte. The partially stabilized zirconia includes crystal particles, the crystal particles include mixed phase particles each having a high-concentration phase and a low-concentration phase, the high-concentration phase being defined such that a concentration of the stabilizer is 4.7 mol % or more, the low-concentration phase being defined as a concentration of the stabilizer is less than 4.7 mol %.

A super hard polycrystalline construction is disclosed as comprising a first region comprising a body of thermally stable polycrystalline diamond material comprising a plurality of intergrown grains of diamond material; a second region forming a substrate to the first region; and a third region interposed between the first and second regions. The third region extends across a surface of the second region along an interface. The interface comprises at least a portion having an uneven topology, and the third region comprises a diamond composite material including a first phase comprising a plurality of non-intergrown super hard grains, said super hard grains comprising diamond grains; and a matrix material. The superhard material and matrix material of the third region form a diamond composite material which is more acid resistant than polycrystalline diamond material having a binder-catalyst phase comprising cobalt, and/or more acid resistant than cemented tungsten carbide material.

The present invention concerns a process for the preparation of a porous carbon structure comprising the steps: a) providing a template comprising voids, b) filling of at least part of the voids with a precursor for the formation of the porous carbon structure, c) carbonizing the precursor for the formation of the porous carbon structure and d) removing at least part of the template. In preferred embodiments the precursor for the formation of the porous carbon structure is a formaldehyde-phenol resin, especially a cross-linked resorcinol-formaldehyde resin. The template further preferably comprises a block copolymer and an amphiphilic molecule, wherein the block copolymer comprises polymeric units of at least one lipophilic monomer and polymeric units of at least one hydrophilic monomer. Further preferred is a process wherein the template comprises a bimodal mixture of particles of silicon dioxide.

A method of forming a super hard polycrystalline construction comprises forming a liquid suspension of a first mass of nano-ceramic particles and a mass of particles or grains of super hard material having an average particle or grain size of 1 or more microns, dispersing the particles or grains in the liquid suspension to form a substantially homogeneous suspension, drying the suspension to form an admix of the nano-ceramic and super hard grains or particles, and forming a pre-sinter assembly comprising the admix. The pre-sinter assembly is then sintered to form a body of polycrystalline super hard material comprising a first fraction of super hard grains and a second fraction, the nano-ceramic particles forming the second fraction.

The super hard grains are spaced along at least a portion of the peripheral surface by one or more nano-ceramic grains, the super hard grains having a greater average grain size than that of the grains in the second fraction which have an average size of less than around 999 nm.

A process for manufacturing ceramic-metal composite material, comprises dissolving ceramic powder into water to obtain an aqueous solution of ceramic; mixing metal powder having a multimodal particle size where largest particle size is one fourth of the minimum dimension of a device, with the aqueous solution of ceramic to obtain a powder containing ceramic precipitated on the surface of metal particles; mixing the powder containing ceramic precipitated on the surface of the metal particles, with ceramic powder having a particle size below 50 μm, to obtain a powder mixture; adding saturated aqueous solution of ceramic to the powder mixture to obtain an aqueous composition containing ceramic and metal; compressing the aqueous composition to form a disc of ceramic-metal composite material containing ceramic and metal; and removing water from the ceramic-metal composite material; wherein ceramic content of the disc is 10 vol-% to 35 vol-%. Alternatively, ceramic-ceramic composite material may be manufactured.